I like Cape Dory Sailboats, a lot, especially my current tiller equipped 28.
That being said I would have to agree that planning on making money off a restoration is questionable. There are several Cape Dories that are currently available on the web that have undergone extensive renovation from the keel up and are price accordingly. While worth every penny due to their condition they appeal to a smaller set of sailors who want a turnkey boat and are willing to pay a premium price. The following link is an example of a company that has done Cape Dory renovations and seem to make it a money making proposition.
Restorations - Finger Lakes Boating Center
Recommend you visit the Cape Dory Association web site where you will find Cape Dory boats and their loyal followers. As you will note there are currently 28s that range from 12k to 30k and each are worth the price based upon condition and equipment. You will also find on occasion the die heart Cape Dory lover (noted by Rob) who will gift his boat over to someone willing to bring it back to full glory. However, as my admiral is quick and correct to point out, there is no such things as a free boat.
You didn't mention the Volvo Penta that you had available but the 28 accepts a Volvo Penta 2002 as a perfect fit. That being said that engine does not bring much additional value in terms of configuration. I know this because my 28 has a 2002, which I have had no issues with and have performed flawlessly for me.
Negotiate with the seller for a reduced price, bring the boat back to life and enjoy its use. Do a great job and you'll can recoup some of your costs while retaining all of the experiences. You will find yourself the owner of a Yacht which is to sailboats what a Jeep Wrangler is to an automobile.
I'll never forget the first two trips I took in my Cape Dory 28 when I was complimented about sailing into my slip at the marina (the bolt holding my heat exchanger had backed out resulting in my losing coolant) and the locals were all commenting about those Cape Dory sailors who sail everywhere and don't need engines. And arriving at Crisfield Maryland where a crew who had been stuck there for three days due to weather, expressed amazement that someone had sailed in off of Tangier Sound, only to look out from the boathouse and note, "O you have a Cape Dory, that explains it". Just remember to practice backing up and don't every try it in front of witnesses!